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      1 /*
      2  * Copyright (C) 2008 The Guava Authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  * http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.google.common.collect.testing.testers;
     18 
     19 import static com.google.common.collect.testing.features.CollectionSize.ZERO;
     20 import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
     21 import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_QUERIES;
     22 import static com.google.common.collect.testing.features.MapFeature.SUPPORTS_REMOVE;
     23 
     24 import com.google.common.collect.testing.AbstractMapTester;
     25 import com.google.common.collect.testing.WrongType;
     26 import com.google.common.collect.testing.features.CollectionSize;
     27 import com.google.common.collect.testing.features.MapFeature;
     28 
     29 /**
     30  * A generic JUnit test which tests {@code remove} operations on a map. Can't be
     31  * invoked directly; please see
     32  * {@link com.google.common.collect.testing.MapTestSuiteBuilder}.
     33  *
     34  * <p>This class is GWT compatible.
     35  *
     36  * @author George van den Driessche
     37  * @author Chris Povirk
     38  */
     39 @SuppressWarnings("unchecked") // too many "unchecked generic array creations"
     40 public class MapRemoveTester<K, V> extends AbstractMapTester<K, V> {
     41   @MapFeature.Require(SUPPORTS_REMOVE)
     42   @CollectionSize.Require(absent = ZERO)
     43   public void testRemove_present() {
     44     int initialSize = getMap().size();
     45     assertEquals("remove(present) should return the associated value",
     46         samples.e0.getValue(), getMap().remove(samples.e0.getKey()));
     47     assertEquals("remove(present) should decrease a map's size by one.",
     48         initialSize - 1, getMap().size());
     49     expectMissing(samples.e0);
     50   }
     51 
     52   @MapFeature.Require(SUPPORTS_REMOVE)
     53   public void testRemove_notPresent() {
     54     assertNull("remove(notPresent) should return null",
     55         getMap().remove(samples.e3.getKey()));
     56     expectUnchanged();
     57   }
     58 
     59   @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_KEYS})
     60   @CollectionSize.Require(absent = ZERO)
     61   public void testRemove_nullPresent() {
     62     initMapWithNullKey();
     63 
     64     int initialSize = getMap().size();
     65     assertEquals("remove(null) should return the associated value",
     66         getValueForNullKey(), getMap().remove(null));
     67     assertEquals("remove(present) should decrease a map's size by one.",
     68         initialSize - 1, getMap().size());
     69     expectMissing(entry(null, getValueForNullKey()));
     70   }
     71 
     72   @MapFeature.Require(absent = SUPPORTS_REMOVE)
     73   @CollectionSize.Require(absent = ZERO)
     74   public void testRemove_unsupported() {
     75     try {
     76       getMap().remove(samples.e0.getKey());
     77       fail("remove(present) should throw UnsupportedOperationException");
     78     } catch (UnsupportedOperationException expected) {
     79     }
     80     expectUnchanged();
     81     assertEquals("remove(present) should not remove the element",
     82         samples.e0.getValue(), get(samples.e0.getKey()));
     83   }
     84 
     85   @MapFeature.Require(absent = SUPPORTS_REMOVE)
     86   public void testRemove_unsupportedNotPresent() {
     87     try {
     88       assertNull("remove(notPresent) should return null or throw "
     89           + "UnsupportedOperationException",
     90           getMap().remove(samples.e3.getKey()));
     91     } catch (UnsupportedOperationException tolerated) {
     92     }
     93     expectUnchanged();
     94     expectMissing(samples.e3);
     95   }
     96 
     97   @MapFeature.Require(
     98       value = SUPPORTS_REMOVE,
     99       absent = ALLOWS_NULL_QUERIES)
    100   public void testRemove_nullQueriesNotSupported() {
    101     try {
    102       assertNull("remove(null) should return null or throw "
    103           + "NullPointerException",
    104           getMap().remove(null));
    105     } catch (NullPointerException tolerated) {
    106     }
    107     expectUnchanged();
    108   }
    109 
    110   @MapFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_QUERIES})
    111   public void testRemove_nullSupportedMissing() {
    112     assertNull("remove(null) should return null", getMap().remove(null));
    113     expectUnchanged();
    114   }
    115 
    116   @MapFeature.Require(SUPPORTS_REMOVE)
    117   public void testRemove_wrongType() {
    118     try {
    119       assertNull(getMap().remove(WrongType.VALUE));
    120     } catch (ClassCastException tolerated) {
    121     }
    122     expectUnchanged();
    123   }
    124 }
    125